The invention lies in the telecommunications field. Specifically, the invention pertains to a method and a configuration which provides performance features for mobile subscribers via a communications network.
Because working conditions are becoming increasingly flexible in terms of time and location, the number of employees who do not carry out their professional tasks at their assigned workplace office is rising continuously. The publication xe2x80x9cDas virtuelle Bxc3xcroxe2x80x9d [The Virtual Office], telcomreport, Issue 4, 1997, Siemens AG Berlin and Munich describes that for tasks to be carried out effectively outside the company location it is necessary to have access to the communications performance features provided in the company""s local communications network, irrespective of the location of the employee. These performance features include the performance features, such as, for example, the setting-up of a conference circuit or signaling of the inputting of a message, which are additional to the standard performance features provided in a, say, ISDN-oriented communications network.
In order to enable the performance features implemented by a communications system to be made available at an external terminal in the same way as at an internal terminal, it has been proposed for terminal-oriented signaling information, such as is usually transferred within the scope of a signaling protocol between the communications system and internal terminals which are connected to it, to be made available between the communications system and the external terminal via a data link which is set up in addition to the user data link.
This requires two user data links to be made available at the external terminal in order to transfer the user data via a first user data link (for example a first ISDN-B channel) and the terminal-oriented signaling information via a second user data link (for example a second ISDN-B channel). Furthermore, it is necessary for the first terminal to be designed in such a way that the terminal-oriented signaling information which has been transferred can be evaluated.
It is accordingly an object of the invention to provide a method and device for making available performance features in a communications system to an external terminal, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type, while making minimum requirements of the external terminal.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method of providing performance features made available to internal subscriber terminating lines in a communications system to an external terminal, the method which comprises:
communicating between internal terminals and a communications system within a defined signaling protocol;
providing a teleworking subscriber line module in the communications system;
setting up a voice link between an external terminal and the teleworking subscriber line module of the communications system by signing on the external terminal with the communications system;
transferring via the voice link control information input at the external terminal in the form of assigned DTMF signals to the teleworking subscriber line module; and
identifying the DTMF signals received at the teleworking subscriber line module, converting the DTMF signals into terminal-oriented signaling information according to the defined signaling protocol, and transferring the converted DTMF signals to a control unit of the communications system.
In other words, performance features implemented by a communications system can be made available at an external terminal. For that purpose, control information in the form of DTMF signals (DTMF=Dual Tone Multi-Frequency) is transferred via a voice link from the external terminal to the teleworking subscriber line module in the communications system. For the DTMF signals, each key of a terminal is assigned a characteristic signal which is transferred via the voice link when the key is activated. The signal differs in terms of frequency and signal duration from the data which are usually transferred via the voice link, so that the signals can be identified and evaluated at the teleworking subscriber line module.
A significant advantage of the invention is that the external terminal can be connected to the communications system via any communications network, for example an analog communications network, an ISDN-oriented communications network or a radio network. All that is required of the external terminal is merely that the MFD (Multi-Frequency Dialing method) for generating DTMF signals is supported by the external terminal.
A further advantage of the invention is that the system components which are necessary for the so-called teleworking concept which can be implemented by the invention can easily be integrated into an existing communications system.
In accordance with an added feature of the invention, a teleworking computer for controlling the teleworking subscriber line module is connected to the teleworking subscriber line module via a local computer network. The control information received at the teleworking subscriber line module is thereby transferred to the control unit via the teleworking computer.
In accordance with an additional feature of the invention, a sign-on authorization is checked with the teleworking computer by referring to subscriber-specific data transmitted from the external terminal.
In accordance with another feature of the invention, in the course of a sign-on operation, the teleworking computer assigns a virtual subscriber connection port of the teleworking subscriber line module to the external terminal, and data directed by the control unit to an internal subscriber terminating line as identified by the subscriber-specific data is rerouted to the virtual subscriber connection port.
In accordance with a further feature of the invention, data transferred to the external terminal are output via the virtual subscriber connection port at the external terminal. The output may be in the form of an audible announcement or a visual display.
In accordance with again a further feature of the invention, a connection is set up between the external terminal and a further terminal, subsequently to a sign-on, by routing the terminal link between the external terminal and a further terminal via the teleworking subscriber line module.
In accordance with a preferred embodiment, the control information is transferred from the external terminal to the communications system via the terminal link in a DTMF signal format.
In accordance with again another feature of the invention, if a DTMF signal cannot be identified at the teleworking subscriber line module, the DTMF signal is transferred to the further terminal.
In accordance with again an added feature of the invention, a plurality of terminal links are simultaneously routed in each case between one external terminal signed on to the communications system and one further terminal via the teleworking subscriber line module.
In accordance with again an additional feature of the invention, the internal subscriber terminating line is set up only in the form of a virtual connection port.
With the above and other objects in view there is also provided, in accordance with the invention, a teleworking subscriber line module in a communications system, the communications system having a control unit and a switching matrix unit with a bi-directional, time-division-multiplex-oriented port. The module comprises:
a signaling unit having an HDLC interface for connecting to a control unit of a communications system;
a PCM connection unit having a PCM interface for connecting to a bi-directional, time-division-multiplex-oriented port of a switching matrix unit of the communications system, the PCM connection unit having a DTMF connection unit for detecting and evaluating control information received in DTMF signals via a user data link; and
a conversion unit connected between the signaling unit and the PCM connection unit for converting data to a given transmission protocol and transferring the data between the signaling unit and the PCM connection unit.
In accordance with yet an added feature of the invention, a LAN connection unit with a LAN interface connects the subscriber line module to a local computer network.
In accordance with a concomitant feature of the invention, there is provided an output unit for transferring messages stored in the teleworking subscriber line module to an external terminal. The output unit transfers the messages in a format to be output by the external terminal as an announcement or a visual display.
One advantage of refinements of the invention is that a subscriber who has signed on to the communications system at an external terminal can be accessed on the same call number as the internal terminal assigned to that person.
By assigning virtual connection portsxe2x80x94often referred to as pseudo-connection ports in the literaturexe2x80x94subscribers can utilize the performance features of the communications system at an external terminal even if they do not have a physically existing internal terminal assigned to them.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and configuration for providing performance features for mobile subscribers via a communications network, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.